Composite floor or roof support



Nov. 19, 1957 a D D, HARRlsQN v 2,813,310

COMPOSITE FLOOR OR ROOF SUPPORT Filed Juiy 29, 195s 4 Sheets-Sheet 1.

r l l i l f L lInventor DGA-LB UEX H/MR/J'/V Nov. 19, 1957 D. D. HARRlsoN COMPOSITE FLooRvoR RooF SUPPORT `4 Sheets-Sheet 2 Filed July 29, 1953 A Inventor 00A/AID DEW HARK /J'V By n.5 s. MMM( Nov. 19, 1957 D. D. HARRISON 2,813,310

` COMPOSITE FLOOR OR ROOF SUPPORT Filed July 29, 1953 4 Sheets-Sheet 3 'Inventolr DONAL DfX HARK/ION By ,4.5 6. 'eswc Agent;

Nov. 19,1957

Filed July 29, 1953 F/GS.

D. D. HARRISON COMPOSITE FLOOR 0R lR001? SUPPORT 4 Sheets-Sheet 4 -lnuemor DONALD DEX HARK/50N 13y A5, c. dew

Ajem

United States Patent fiiice 2,813,310 latented Nov. 19, 1957 '2,813,310 p coMPosrrE FLooR on RooF SUPPORT Donald Dex Harrison, London, England, assignor, by direct and mesne assignments, to Dex (Prefabrlcatlons) Limited, London, England, a British company Application July 29, 1953, Serial No. 371,089 Claims priority, application Great `Britain July 31, 1952 4`Claims.` (Cl. 20.5)

This invention relates to building structures having four separate beam parts two of which extend transversely of the other two, and having four adjacent ends secured together by connecting means, and is in particular concerned with Vroof and floor structures.

The main object of the invention is to provide improved connecting means including a pair of tensioning filaments, one filament extending inthe general direction of one pair of beam parts, and the other filament extending in the general direction of the other pair of beam parts, said filaments being secured to the structure at their ends l and tensioned so as to urge their respective pairs of beam parts towards each other. s

The beams thus may be built up from a number of parts which may be of standardised size which can be assembled on the site and may be built up to form various lengths ot' beams and the beams may be connected across each other horizontally and/ or vertically to form a :trarne-` like roof or floor or wall structure.

The connecting devices may comprise a pair of cruciform plates shaped to engage the beam parts at their ends on opposite sides, and the strut means is fixed to one of said plates.

The plates may be secured together by a central bolt which passes through an abutment block located between the ends of the beam parts, one end of said bolt being located in a depression in the adjacent end of the strut means.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawings wherein:

Figure 1 is a plan view of part of a roof structure made in accordance with `the invention;

Figure 2 is a section on the line 2-2 on Figure 1;

Figure 3 is a plan view of a detail to be described;

Figure 4 is a vertical sectional view of part of the structure at the junction of the beam parts, approximately on the line 4-4 on Figure 1; l

Figure 5 is an elevation of Va strut means used in said structure;

Figure 6 is a top plan of said strut means;

Figure 7 is a sectional view of said strut means on the line 7-7 on Figure 5.

Figure 8 is a section on the line 8-8 on Figure 5;

Figure 9 is a vertical sectional view approximately on the line 99 on Figure 1; and Figure l0 is a view similar to Figure 5 but also showing the tensioned filaments, beam ends, and means for connecting the strut means to the beam ends.

The part roof structure of Figure 1 can be extended in any one or more directions and is composed of beams i 10, 11, 12, 13, crossed by beams 14, 15, 16, 17, to form squares (or if desired rectangles or rhombs). Each beam is composed of a number of separate beam parts. Thus beam 12 has parts 20, 21, 22; 13 has parts 23, 24, 25; and 16 for example has parts 26, 27, 28. The ends of the beam parts adjacent each other are thus disposed with two (e. g. 27, 28) extending transversely of the other or are separated byan abutment block which has a boltjhole 31 therethrough.

Each of the four positions where the beams 15, 16 cross the beams 11, 12 is provided with a transverse projection or strut 33 extending from the beam ends downwardly some distance as shown in Figure 2. Tensioning wires or filaments are provided at least one for each beam so that each strut 33 carries two filaments extending transversely to each other, each in the general direction of its respective beam. Thus the filament 34 shown in Figures l and 2 is in the general direction of the beam 16 and filaments 35, 36 are in the general direction ofjthe beams 11, 12. The filaments are attached to the ends of 30 (Figure 3) the plurality of the beam parts and between their ends they engage the struts whereby they are held spaced from the beams. They are then tensioned as for example by turnbuckles 37 (Figure 2). In the example shown each filament passes over two adjacent struts but in other examples they may pass` over a single strut or more than than two struts.

The adjacent ends of the `beam parts at each juncture extremities as at 42, 43 Figure 4, and wings: or webs 45,

46, apertured at 47, 48. j l

The ends ofthe beam parts are recessed to receive the thickened ends of the limbs of the plates. `The plates are placed on opposite sides of the beam (above and below) and fixed together by a bolt 49. A

The `strut shown in` Figures 5 to 8 is intended to be made up from four wooden bars 50, 51, 52 and 53, glued together at 54 (Figure 8) to form a strut having a recess 55 at the top, vertical slotsj56 disposed crosswise of each other at the top, slots57, 58 disposed crosswise of each other at the bottom, andfthe whole tapering to the lower with the bolt 49 in the recess 55, the wings 45, 46 in the slots 56, and bolts or pegs inthe bolt holes 47, 48 and 60.

The filaments such as 34, 35 fit in the slots 57, 58. The strut isshown-in Figure 10 fixed in this manner and engaged by the filaments.

The ends of the filaments may be secured in any convenient manner. For example as shown in Figure 9, the abutment block 3h0 is inwtheform of"` a hollow `metal casting provided with apertures 65, 66, and the adjacent ends of the beams 67, 68 are drilled at 69, 70 to receive .the filaments 71 (one only being shown) the ends of which project into the block 30 and are threaded to receive nuts 72. The beam ends are supportedby a column 74 to which the plate 41 is attached by tapered pegs 75, 76. A roofing panel 77 is attached to the top plate 40 by pegs 79, 80 and a cover plate 81 is fitted over the top plate 40.

The structure may be built up on the site as follows: The elongated beam parts such as 20, 21, 22 are inserted between the pairs of top and bottom plates 40, 41 to form a series of beams 10, 11, 12 and 14, 15, 16 at right angles to each other. As many units are put together as are required and the filaments such as 34, 35, 36 are then positioned on the projections or struts and an initial tension is imparted to the wires. This tension induces a corresponding compressive stress into the beam parts which is taken up at the several joints in the form of friction between the bearing ends of the parts and the opposing surface on which they impinge. This process of pretensioning is carried to a predetermined degree, which may be varied at will until the limiting stress in the materials is reached. At a suitable stage the nuts are tightened on the bolts 49 (having only been loosely tightf ened prior to this to allowv for the beam parts to slip along the joint so that friction' at their ends can be developed). The tightening of Anuts serves to compress the top and bottom plates 40, 41 of the connecting devices on to the beam parts and allow for'the transference of further stresses through the plates.

The joint so formed is capable of transferringstress either via the end of the part lto b e-joinedor via the upper and lower plates and in practice both parts of the joint take stress, since pretensioning is only used up' to a certain degree.

This form of joint is capable of transferring all the stress that can be developed in thefbeam parts and the beam parts can be made to fail rstas the weakest element in the scheme. This ability of the joint to transfer the stress is a particular advantage of the invention.

The beam structure is now capable of taking load and the incidence of the load carried as between the several resulting beams can be varied at the designers discretion according to the amount of tension imparted t0 the laments.

The advantages of being able to .distribute load in this manner, in two directions, are very important since the distribution of load enables each beam to be of lighter construction than if only one direction of span could be used and this facility results in economies in the scheme as a whole wherever spans approximating to rectangles approaching a square can be arranged.

In the case of rectangles (spans other than square) the depth of the beam can be increased by using longer struts or providing struts each having two or more hooks or slots at different distances along its length and placing the laments in a lower slot. Thus the longer beams can be made as stiff as the shorter beams by this very simple operation while still using thesame standard lelements and keeping to the same stresses, up tothe limit of the length of projections.

Special advantages of the invention are as follows:

(1) From a limited number of standardised parts a wide variety of structures can be built up.

(2) The standard parts are arranged for compactness of packaging.

(3) Erection on the site is speedy and dry in technique, minimising the use of site labour.'

(4) The structure is demountable and allows 100% recovery value.

(5) The cellular nature of the system which permits columns to be placed almost at will at any intersection (in place of the struts) results in a freeing of the plan from the rigidities imposed by orthodox structural systems.

(6) The facility for two way spanning and the method whereby the whole of the stress is transferred at the joints permit economies of material to be'made.

(7) The structure in accordance with the invention can be made in various alternative materials (for exampley timber, concrete, steel, and aluminium alloy) thereby facilitating its application to widely ditfering conditions.

I claim:

1. A building structure having four separate beams disposed in a common plane, two of said beams extending transversely of the other two, said beams having four adjacent ends intersecting at a common point, the remote ends ofat least some of said beams being supported on vertical uprights, a pair of clamping plates positioned `above and below said adjacent ends, said adjacent ends being interconnected and supported by said clamping plates, a bolt' drawing said clamping plates towards each other and clamping said ends together, a separate compression strut disposed on one of said clamping plates and extending transversely of all said beams, and a pair of crossing tensioned rods engaging an end of said strut and spaced thereby from the beams, one rod extending inthe general direction of one pair of beams, and the other rod extending in the general direction of the other pair of beams, the ends of said rods being held fixed adjacent said uprights, said rods being tensioned and thereby urging their respective pairs of beams towards each other, the parts of the rods adjacent the struts being spaced further from the beams than the parts at the ends of the rods, said adjacent beam ends being supported solely by said rods, strut, plates, and bolt.'

2 A structure as claimed in claim 1 wherein the strut has slots therein crosswise of each other at its lower end, said slots receiving said crossed rods.

'3. A structure as claimed in claim 1Y Yhaving webs on said plates, slots in the strut crosswise of each other` at its upper end, said slots receiving the webs, holes in the webs and strut, and connecting elementspassing through said holes and anchoring said webs insaid slots.

4. A structure as claimed in claim l havinga hollow abutment block at the remote end-of `a beam adjacenty one of said uprights, said abutment block being secured to said upright, one end of a rod passing through an inclined hole in the remote end of the beam and through an aligned hole in said hollow abutment block, and a nut on the end of said rod located within said block anchoring said rod to said block.

References Cited in the file of this patent UNITED STATES PATENTS 

